Added printable instructions; fixed &amp; issue showing up in titles
Printable Instructions
Valid courses still when included with invalid ones
Error-tolerant computation of missing prereqs

	In a pre-req list, if there was a null course, the whole
	pre-req computation would abort.  We now silently ignore
	the null course.
Add creation date to saved graphs
Robustly update welcome page on load
Remove redundant "New Program" description
Enter on the subject list now adds subject
[dotgraph] Fixed non-global regex in string escaping
Added coop banners and fixed pruning bug.

	Though the computation of edge pruning was
	correct, a capitalization mistake prevented
	it from taking any effect!